Electric motors tend to heat when operating and therefore cooling fins and/or a fan are added therein.
However, motors used to produce force return effects, also called “force feedback” effects, in high-end steering wheels for video games heat up substantially, especially when the user of the steering wheel opposes the forces produced by the motor, for example, when the motor receives an immobility instruction from the shaft of the motor (immobility of the shaft of the motor and therefore immobility of the wheel of the steering wheel), and that at the same time the user insists on rotating the wheel of the steering wheel as these efforts are transmitted mechanically to the motor. Very recently, the motors used to produce the feedback force in high-end steering wheels for video games are brushless motors. In order to prevent the problems caused by the thermal latency, i.e. the time for transmitting the internal heat to the outside and for preventing the temperature from degrading the motor, the forces of the user aren't countered or are countered less which degrades the realism of the force feedback. The power of the motor is under-exploited in order to preserve the lifecycle of the product. This is all the more so critical if the motor has mobile coils therefore farther away from the outer surface of the motor. Consequently, the transmission of the heat was carried out with yet a further delay.
Currently, there are separate solutions used to overcome this problem:                The first is the use of several motors, acting together, instead of a single motor;        The second is the presence of an external fan generally located next to the single motor and which ventilates external cooling fins.        
It is also known to integrate a set of blades inside a brushless electric motor on the rotor. But, this set of blades is then fixed to the shaft of the electric motor. And when the motor is blocked, which causes most problems regarding the heating of the coils (to which electric current is supplied for causing the rotation of the rotor), these blades are not functional. These blades can't cool the motor because they don't rotate when the shaft of the motor is immobile.
Using several motors is expensive and complex to implement.
The external fan is not always sufficient to cool the motor and more precisely certain internal zones of the motor. The lifecycle of the motor is then reduced. The fan therefore has to be imposing in order to partially offset its low effectiveness without causing excessive noise. The casing of the steering wheel is therefore not compact. These solutions for cooling via external convection (fan) or by conduction (radiator) do not treat the heat source namely the coil and do not make it possible to homogenously dissipate the heat on each one of the coils. On the other hand, some of the most recent steering wheels have a brushless motor of which the casing is smooth and supplied at the origin without cooling fins. On this casing a tubular part is nested comprising cooling fins extending radially. A fan is then placed vertically at a distance from the motor in such a way that a flow of air circulates over these cooling fins. The oldest steering wheels have a brush motor of which the casing is smooth but on which is fixed a radiator which extends radially. A vertical or horizontal fan is placed at a distance from the motor in such a way that a flow of air circulates on this radiator.
A brushless motor comprising a set of blades fixed to the shaft of the electric motor has the disadvantage of a rotation of the blades identical to the rotation of the shaft of the motor (the blades cannot rotate faster than the shaft, or in the opposite direction). The blades slow down the rotation of the rotor and therefore increase the consumption of the motor. The presence of the fan driven by the motor itself gives the whole a relatively large size.
A patent FR3000628 has attempted to overcome some drawbacks of asynchronous motors which are used to drive a load (the motor shown in FIG. 1 of Patent FR3000628 is an aircraft wheel drive which is suitable for being integrated in the base of the landing gear to permit movement of the aircraft when on the ground in the absence of propulsion provided by the reactors), with limited results (however in such use, the motor shaft isn't blocked when the motor is powered). The patent FR3000628 teaches that a flow of air circulates in an annular space defined by an envelope surrounding the stator of a motor and a casing of the motor. As a consequence, it has the disadvantage of not blowing a flow of air inside of the stator, between the coils; therefor the cooling isn't uniform (the periphery of the winding—i.e. the portion of the winding which is contact with the envelope—is better cooled than the portion of the winding which is close to the magnet) and has low efficiency. It doesn't solve the problems caused by the thermal latency, i.e. here the time for transmitting the internal heat to the envelope for preventing the temperature from degrading the motor. It further has the disadvantage that one of the ends of the motor shaft can't be used because the auxiliary motor driving the fan is placed at one side of the motor casing. Moreover, it is complex due to a number of parts. Finally, the coils of the fan aren't cooled by the flow of air.